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HORMONAL FACTORS INFLUENCING SALT APPETITE IN LACTATION
Author(s) -
Shulkes AA,
Covelli Memma D,
Denton DA,
Nelson JF
Publication year - 1972
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1972.79
Subject(s) - lactation , prolactin , oxytocin , endocrinology , medicine , sodium , appetite , chemistry , hormone , zoology , excretion , biology , pregnancy , genetics , organic chemistry
Summary The appetite of wild rabbits ( Oryctolagus cuniculus (L)) for 500 mEq/1 solutions of NaCl, KCl, MgCl 2 , and CaCl 2 , was studied during daily injections of ovine prolactin, ovine growth hormone or synthetic oxytocin. The animals were individually caged and external sodium balances were made. Under all experimental conditions the animals were obtaining ample sodium from the food, as evidenced by a substantial urinary sodium excretion. Injection of 50 I.U. prolactin significantly increased NaCl intake from a control value of 0·4 mEq/day to 2·3 mEq/day during the course of injections. CaCl 2 intake was also significantly increased. The mean daily intake of NaCl during the oxytocin treatment was 1·34 mEq/day, 21/2; times the control value. Water intake was reduced but there were no significant changes in the intakes of KCl, MgCl 2 and CaCl 2 ,. Growth hormone had no effect on electrolyte or H 2 O intakes. Previously reported work shows that a significant increase in NaCl intake occurs during lactation in the wild rabbit. The metabolic studies indicate that, as in lactation, the increase in NaCl intake witb prolactin and oxytocin occurs without any preceding change in urinary sodium excretion. The results suggest that the increase in NaCl intake in lactation is hormonal in origin and not caused by the sodium requirements of lactation.